House Flies
Order:
Diptera
Family: Musicdae
Scientific Name: Musca domestica Linnaeus
The house fly, Musca domestica,
is worldwide in distribution. It
is the most common fly around homes.
While in many cases they are considered nuisance pests, these flies
are associated with more than 100 disease-causing organisms, which can
be transmitted to humans and animals through feces, regurgitation while
feeding, and contaminated body parts.
Identification
The adult housefly is about 1/8- to ¼-inch long. It is dull gray in color, the sides of its abdomen are pale, and it has four narrow, black longitudinal stripes running down its thorax. In place of a second pair of wings are halteres, club-shaped organs used for balance. The fourth longitudinal vein of the wing is sharply bent forward near the tip.
The mature, cigar-shaped larva is ¼- to 3/8-inch long, eyeless, legless and cream-colored, with a greasy appearance. The head is pointed and has a pair of mouth hooks. The blunt rear segment has posterior spiracles, which are composed of twisting slits surrounded by a black oval ridge, or peritreme. The peritreme has a donut-shaped structure (button) attached to its inner edge.
Biology and Habits
Adults are general feeders and are attracted to nearly anything moist and decaying, from food products to garbage to excrement. They feed by regurgitating on the food source and then ingesting the liquefied material with their sponging mouth parts. During this process they ingest many disease-causing organisms or pick them up on their bodies.
Houseflies undergo complete metamorphosis. The female lay eggs singly in batches of 75 to 150 on any moist medium with sufficient food or larval development. She lays 350 to 900 eggs in her lifetime. Eggs develop into first instar larvae in less than one day, and the larvae go through three instars in as little as seven days. The larvae then seek out a drier habitat for pupation, which can last from three days to four weeks. As many as 10 to 12 generations can occur during the summer. Adult houseflies generally live for 15 to 25 days.
Adults can migrate up to
20 miles from breeding sites; however, they are usually found within a
mile or two. During the day adults tend to rest less than five feet from
the ground on walls, floors, and other objects.
At night they rest more than five feet above the floor, often on
ceilings, wires, lights and plants.
Control
Housefly control begins with correct identification of the pest. The subsequent inspection includes locating all resting and larval development sites. Because the adults often rest in breeding areas, it may be helpful to inspect at night.
Sanitation, or source reduction, is the most important step in fly control because it eliminates larval breeding sites. When successful, it significantly reduces the need for pesticide applications. If trash cans are the problem, empty and clean them at least weekly to disrupt the developmental cycle. In areas such as stables, barns, pet kennels and poultry houses, animal feces must be spread out to dry or disposed of weekly.
Take mechanical control measures including insect-proof garbage containers, self-closing doors, screening, caulking and air curtains. Use electric flytraps, sticky traps and other devices to reduce adult fly populations indoors and out.
Insecticide applications are directed to adults because sanitation and removal are the best control measures for larval breeding sites. Dispersal techniques for fly control include baits, aerosols and residual insecticides. The most widely used pesticides are emulsifiable concentrates , wettable powders and microencapsulated formulations. The site of application and labeling determine product selection. Most residual applications are made to the daytime and evening resting sites. Perform ultra-low volume and aerosol applications when the adults are most active and there is the least risk of drift, surface contamination, and human or animal exposure.
(Courtesy of the National Pest Control Association.)